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arXiv · 1011.4913

Observation of novel interference patterns in Bi2-xFexTe3+d by Fourier transform scanning tunneling spectroscopy

Y. Okada·C. Dhital·Wen-Wen Zhou·Hsin Lin·S. Basak·A. Bansil·Y. -B. Huang·H. Ding·Z. Wang·Stephen D. Wilson·V. Madhavan
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Abstract

In topological insulators (TI), strong spin-orbit coupling results in non-trivial scattering processes of the surface states, whose effects include suppressed back scattering1, 2, 3, 4 weak anti-localization5, 6 and the possibility of an exotic Kondo effect that mimics graphene7. Introducing time reversal breaking perturbations and establishing long-range magnetic order has been theorized to lead to the formation of quantized magnetoelectric phenomena8, fractionalized charge excitations, and the appearance of quantum wire states9. A key, elusive, step in exploring these and other novel electronic phases is the experimental observation of charge backscattering due to spin-flip processes at the surface of a magnetically-doped TI. Here we utilize Fourier transform scanning tunneling spectroscopy (FT-STS) to probe the surface of a magnetically doped TI, Bi2-xFexTe3+d. Our measurements show the appearance of a hitherto unobserved channel of electronic backscattering along surface q-vector \Gamma\kappa. By combining FT-STS with angle-resolved photoemission data, we identify the momentum space origins of the observed q-vectors, which on comparison to a model calculation are enhanced by spin-flip scattering. Our findings present compelling evidence for the first spatial and momentum resolved measurements of magnetic impurity induced backscattering in a prototypical TI.

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Y. Okada, C. Dhital, Wen-Wen Zhou, Hsin Lin, S. Basak, A. Bansil, Y. -B. Huang, H. Ding, Z. Wang, Stephen D. Wilson, V. Madhavan. 2010-11-22. Observation of novel interference patterns in Bi2-xFexTe3+d by Fourier transform scanning tunneling spectroscopy. https://arxiv.org/abs/1011.4913

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